The invention relates to electric utility meters and more particularly to a method and means of preventing reversal of the orientation of the meter in its base socket.
Theft of electricity has always been a problem and the problem has been growing in magnitude due to the increasing cost of electrical energy. One method of stealing electricity is to reverse the orientation of the electric utility meter with respect to the meter base socket so that the values displayed on the meter are caused to decrease with continued electricity usage. This reversal is generally possible because most meter and socket assemblies have four identical and vertically symmetrical plugs and four identical and vertically symmetrical receptacles which are respectively disposed at the corners of a rectangle.
A number of approaches to prevent reversal of the electric utility meter in its socket have been used. For example, one approach is to arrange the meter plugs and base receptacles in an asymmetric manner so that the meter may be assembled in one orientation only. Such an approach is disclosed in U.S. Pat. No. 4,034,290, issued to Warren. Another approach is to make each plug and receptacle asymmetrical. These approaches, however, have a significant disadvantage in that a totally new meter is required. Thus, in an old installation, the old meter must be replaced, and the base must be replaced or modified.
The present invention overcomes this disadvantage by providing a method and means for preventing standard new or in service electric meters from being reversely assembled in their base sockets. In accordance with this approach, a small member (tab) such as a metal rod is fixed to the meter, suitably adjacent to one of the meter plugs, so as not to interfere with the normal upright insertion of all the meter plugs in their corresponding receptacles. A second member (tab) such as a thin metal sleeve is attached to the base socket, suitably adjacent to the socket receptacle corresponding to the diagonally opposite meter plug, also so as not to interfere with the upright insertion of all the meter plugs in their corresponding receptacles. However, the placement of the second member on the base socket is such that reverse assembly is blocked and prevented by the second member intersecting the first member when reverse assembly is attempted.
This modification to the meter assembly in accordance with the present invention may be accomplished at the site of an installed meter with just a few minutes of labor. Great flexibility is preserved by the fact that the meter rod need only be adapted to the respective meter to which it is mounted, and the base socket sleeve need only be adapted to the respective base socket to which it is to be mounted, so that the two tabs may therefore be installed independently. Another advantage of the invention is that the meter rods and base socket sleeves are inexpensively manufactured. This method and means of electricity theft protection is also advantageous since the tabs are light weight and small in size and therefore easy to carry in service vehicles.